Acetabular Undercoverage, Overcoverage Associated With Hip OA

Elizabeth Hofheinz, M.P.H., M.Ed. • Wed, May 10th, 2017

It’s not often that a natural history museum takes part in advancing our knowledge of hip conditions. But researchers from Case Western Reserve University in Cleveland have done just that. They “mined” the Hamann-Todd Museum at the Cleveland Museum of Natural History in order to help improve treatment of hip osteoarthritis.

Douglas S. Weinberg, M.D. is an orthopedic resident at Case Western and a co-author on the study. He told OTW, “We have been interested in the relationship between FAI [femoral acetabular impingement] parameters, developmental dysplasia of the hip, and arthritis. We felt that using the Hamann-Todd osteological collection would be a good chance to look at a truly randomly sampled population in a unique way.”

“Access to this collection allowed us to measure anatomic parameters that are not otherwise obtainable clinically. To our knowledge, this is one of the first reports on acetabular and femoral head volume in the literature. Doing experiments such as this at the Hamann-Todd Museum allows us to analyze things that cannot be seen on X-ray or MRI. Developing a better understand of acetabular volume and hip joint coverage can have important implications in the treatment of hip dysplasia and femoroacetabular impingement.”

The authors wrote, “A total of 545 cadaveric skeletons (1090 hips) from the Hamann-Todd osteological collection were obtained. Femoral head volume (FHV), acetabular volume (AV), the FHV/AV ratio, acetabular version, alpha angle and anterior femoral neck offset (AFNO) were measured. A validated grading system was used to quantify OA of the hip as minimal, moderate, or severe…”

“Acetabular undercoverage and overcoverage were independent predictors of increased OA of the hip. The alpha angle and AFNO had modest effects, supporting the hypothesis that bony abnormalities both in acetabular dysplasia and FAI are associated with severe OA.”

Dr. Weinberg told OTW, “The most important results are that both acetabular undercoverage and to a lesser extent, overcoverage, were associated with hip osteoarthritis. This data suggests that FAI may have some modest effects on the development of hip osteoarthritis.”

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OK to Place Acetabular Cup Outside “Safe Zone?”

Elizabeth Hofheinz, M.P.H., M.Ed. • Tue, March 15th, 2016

In a retrospective study, Cleveland Clinic researchers set out to test the association between cup positioning and patient-reported functional and general health outcomes, as well as dislocation rate. Going in, the team hypothesized that cup positioning with reference to the native acetabular rim, rather than the reported safe zone, would affect dislocation risk and patient-reported outcomes. All participants received CT imaging when undergoing primary, unilateral total hip arthroplasty (THA) at a single academic center by six surgeons from March 2011-January 2015.

Carlos A. Higuera Rueda, M.D. is an orthopedic surgeon with Cleveland Clinic, Ohio, who co-authored the study. Asked how certain cup positioning might affect patient-reported functional and general health outcomes, he told OTW, The positioning of the components, both acetabular and femoral, would dictate the hip range of motion free of impingement and potentially dictate the mechanics that rule the muscle function around the hip girdle. When the range of motion and the mechanics of the hip are affected, the gait and activities of daily living will be affected. The spine and other joint like the knee and ankle will be affected as well.”

“It was surprising to learn that there is no relationship between positioning the acetabular component on what historically has been defined as a ‘safe zone’ (using the anterior pelvic plane) to prevent instability and have better patient-reported outcomes. Alternatively, we found that the superior and anterior rim of the acetabulum can be used to define version and inclination of the acetabular component in relation to the native acetabulum (and indirectly to the pelvis) and this position correlated better with patient-reported outcomes. This may be explained by the relationship between pelvic tilt, spine anatomy with the hip and other variables that at least in this study are merely assumptions. Future studies should be done to define such relationships with the proposed definition of acetabular component placement.”

Hip and Knee Joint Museum Opens

Biloine W. Young • Tue, April 29th, 2014

In a celebration of 30, 000 joint replacements performed in the hospital—20, 000 hips and 10, 000 knees—the MIOT Hospital in Chennai, India, has established a museum within its premises called The Museum of Arthroplasty. Among the exhibits are models of prosthesis used over the years, including John Charnley’s prosthesis of 1963, which resulted in the world’s first successful hip arthroplasty. The founder and managing director of the hospital, who led the museum development, is P.V.A. Mohandas.

Barry D. Rosario, M.D., the director of the Centre for Knee Replacement Surgery and Computer Navigation, at the MIOT Hospital said, “Osteoarthritis is one of the main indicators for knee replacement, followed by rheumatoid arthritis and other causes such as post traumatic arthritis.” He said that many people under 40 are coming in for joint replacements. We need to ensure that the artificial joints last a lifetime and the patient does not get admitted again.”

Periacetabular Osteotomy for Acetabular Dysplasia

Elizabeth Hofheinz, M.P.H., M.Ed. • Thu, February 22nd, 2018

A team of researchers from Washington University School of Medicine, St. Louis has determined that given the right conditions, the Bernese periacetabular osteotomy (PAO) is an effective treatment for symptomatic acetabular dysplasia.

Joel Wells, M.D., M.P.H. with the Department of Orthopaedic Surgery, University of Texas Southwestern Medical School in Dallas and co-author on the study, told OTW, “I am driven by the unique mechanics of the hip, and how there is no such thing as true idiopathic arthrosis of the hip. Hip preservation is an emerging field with great promise. This is the largest follow up of outcomes of the Bernese PAO.”

The authors wrote, “From July 1994 to August 2008, 238 hips (206 patients) were treated with PAO. Sixty-two had a diagnosis other than classic acetabular dysplasia, and 22 were lost to follow-up. The remaining 154 hips (129 patients) were evaluated at an average of 10.3 years postoperatively. Kaplan-Meier analysis was used to assess survivorship with an end point of total hip arthroplasty (THA). Hips were evaluated using the University of California at Los Angeles (UCLA) Activity Score, modified Harris hip score (mHHS), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscale score. A WOMAC pain subscale score of ≥10 and/or an mHHS of ≤70 were considered to indicate a clinically symptomatic hip.”

Dr. Wells commented to OTW, “The results prove that the Bernese PAO is an effective treatment for symptomatic acetabular dysplasia with very promising long-term results. It also brings to attention of a certain ‘sweet spot’ for acetabular correction, that has not been published before.”

“In an experienced PAO surgeon’s hands, the PAO is a powerful treatment for acetabular dysplasia and it is important to properly correct the deformity. With proper patient selection, surgical technique and recovery, the PAO has proven to be the treatment of choice for acetabular dysplasia.”

Osteoporosis Drug Helps Hip, Knee OA

Elizabeth Hofheinz, M.P.H., M.Ed. • Wed, September 18th, 2013

St George’s, University of London research has found that a drug normally given to osteoporosis sufferers could provide effective pain relief to patients with knee and hip osteoarthritis (OA). The researchers used existing studies to assess the effectiveness of a variety of bisphosphonates in patients suffering from osteoarthritis of the hand, knee, spine and hips.

The researchers looked at 3, 832 patients; in most cases these drugs showed limited pain relief. However, a few studies did show benefit; the bisphosphonate alendronate was found to be more effective for patients with hip osteoarthritis than existing pain relieving drugs. Moreover, the use of zoledronate and alendronate, specific forms of bisphosphonates, improved pain in patients with knee and hip osteoarthritis at six months—but longer term studies are needed.

Dr. Nidhi Sofat, lead researcher, said in the September 5, 2013 news release, “Osteoarthritis is the most common form of arthritis worldwide. It causes damage to bone and cartilage in the joints of affected people. Most treatment is focused around pain relief, as no robust treatments have been discovered that slow down the progression of the disease.

“Our study looked at whether there were any bisphosphonate drugs that have been shown to influence pain and/or disease progression that could be used in osteoarthritis treatment.

“We found that, generally, bisphosphonates are ineffective at managing pain associated with osteoarthritis. But zoledronate and alendronate, which are specific forms of bisphosphonates, do show the potential for effective pain management specifically in patients with knee and hip osteoarthritis.

Dr. Sofat told OTW, “We looked at the use of bisphosphonates in osteoarthritis since OA pain is a major public health concern and there are currently no long-term disease-modifying drugs that are used in OA with proven efficacy. Our most surprising finding was that although we reviewed data from 3, 832 patients in studies worldwide, there was high variability in patient selection and different studies looked at different sites of OA, including the hand, knees, hips and spine. Future studies are needed of bisphosphonates in osteoarthritis in clearly defined subsets of patients, coupled with robust radiographic analysis by cartilage integrity, BML size/composition, synovitis, joint space narrowing and evaluation of clinical biomarkers to more fully evaluate agents that could halt the onset and/or progression of osteoarthritis.”

Shaky Connection between Radiographic Evidence and Pain

Biloine W. Young • Fri, December 18th, 2015

Pain in the hip means a patient has osteoarthritis. Right? Researchers from Boston University School of Medicine say “Not so fast.” According to Caitlyn Fitzpatrick, writing for MD Magazine, in the Farmington Study of 946 patients ages 49 to 79 only 15.6% of patients with frequent hip pain had radiographic signs of osteoarthritis. And only 20.7% of patients with radiographic signs of osteoarthritis had frequent hip pain.

“Given these findings, patients with suspected hip osteoarthritis should be treated regardless of X-ray confirmation, ” said Chan Kim, M.D., corresponding author of the study. He added, “The majority of older subjects with high suspicion for clinical hip osteoarthritis did not have radiographic hip osteoarthritis, suggesting that many older persons with hip osteoarthritis might be missed if diagnosticians relied on hip radiographs to determine if hip pain was due to osteoarthritis.”

The study revealed that hip pain and osteoarthritis do not match up in many cases. Kim noted that failing to catch an osteoarthritis case has harmful consequences. The condition has already been linked to sleep disturbances and heart problems when it requires total joint replacement surgery. And the clinical implication, according to Fitzpatrick, is that test results should not determine whether or not to move forward with a possible hip osteoarthritis diagnosis.